The invention relates to a method for producing blocks of cheese from curd, wherein a curd mass is deposited in at least one cheese mold provided with a follower and in the at least one cheese mold is subjected to a vacuum treatment and pressing treatment, which pressing treatment is carried out while the at least one cheese mold is situated in a holder in which a vacuum prevails.
In cheese production processes, usually a pressing treatment is used to remove whey and air from a curd mass. The curd mass may for instance consist of fresh or already preacidified not yet coherent granular curd particles or assemblies of curd particles, for instance in the form of small lumps, strips or other shapes or, for instance, of a preformed curd block. Through the pressing treatment, a stabilized block is obtained, in that the curd particles adhere to each other. A coherent curd mass, the cheese block, is thereby created and on the outside of the block a rind is formed.
During the pressing treatment, a curd mass is contained in a cheese mold having one or more movable sides. Usually, that is the cover, but designs with movable bottom or sidewall are also possible. For the sake of simplicity, in the following, the starting point is the most common design, a cheese mold having a movable cover. On the movable cover, an external mechanical force is exerted by a pneumatic cylinder or the like.
Usually, the pressing treatment is carried out in a number of successive pressing steps, whereby first an excess of whey and air trapped in the curd mass is removed, and the curd mass is brought into the eventual block form defined by the cheese mold and the cover thereof. The curd particles are thereby pressed against each other for forming a coherent mass; and finally by compaction of the curd mass at the surface of the curd block a rind is formed.
Such a pressing treatment takes much time and requires much energy. In the past, many attempts have been made to accelerate the pressing treatment with the aid of a vacuum treatment and/or to reduce the energy needed therefor while maintaining a good quality of the eventual cheese blocks.
For instance in U.S. Pat. No. 5,082,681 a method for producing blocks of cheddar cheese is described, in which curd blocks obtained from a block former are brought under a high vacuum and then briefly pressed mechanically, while the gas pressure increases to atmospheric pressure, in order to obtain a rind on the block in a short time.
Further, from EP-B-1108362 a method for producing blocks of semihard cheese from fresh granular curd is known, in which, prior to an end pressing treatment under atmospheric pressure, a brief prepressing treatment under a high vacuum of 95% or more is applied to obtain an improved internal structure of the cheese blocks.
From EP 0 742 998 A1 a method of the above-described kind is known for producing blocks of cheese, in which curd is pressed under vacuum during a number of two or more cycles. In each pressing cycle, during a first phase of 20 to 25 minutes, a pressing pressure is exerted on the curd disposed in a cheese mold, while the cheese mold is situated in a vacuum space. Thereupon in a second phase of the respective pressing cycle the pressing pressure is removed and in the vacuum space a pressure is created which is equal to or greater than the atmospheric pressure. The second phase has a duration which is in the order of 30 seconds to two minutes. The pressing pressure may be a mechanically applied pressing pressure, but may also be generated by the difference between the ambient pressure and the vacuum pressure in the vacuum space.